skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High Temperature Compatibility of 60-Watt IHS Materials

Abstract

The 60-Watt Isotopic Heat Source (IHS) utilizes a variety of materials which have been selected for their properties at elevated temperatures. These include iridium, molybdenum, and the T-111 alloy which consists of 90 wt% tantalum, 8 wt% tungsten, and 2 wt% hafnium. Properties of interest in radioisotopic heat source applications include high temperature strength, resistance to oxidation, weldability, and ability to act as a diffusion barrier. Iridium is utilized as a clad for fuel pellets because of its high temperature mechanical properties and good compatibility with carbon and plutonium oxide. Molybdenum retains good high temperature strength and has been used as a diffusion barrier in past applications. However, molybdenum also exhibits poor resistance to oxidation. Therefore, it is necessary to enclose molybdenum components so that they are not exposed to the atmosphere. T-111 exhibits moderate oxidation resistance, good high temperature mechanical properties, and good weldability. For these reasons, it is used as the outer containment boundary for the 60-Watt IHS. Because the temperature in GPHS fueled dads is on the order of 1000 degrees Celsius in the 60-W configuration, the potential for diffusion of dissimilar materials from one into another exists. Deleterious effects of diffusion can include degradation of mechanicalmore » strength through the formation of brittle intermetallics, degradation of mechanical properties through simple alloying, or formation of voids through the Kirkendall effect. Because of the possibility of these effects, design methodology calls for use of diffusion barriers between materials likely to exhibit interdiffusion at elevated temperatures. The necessity to assure the long term integrity of the 60-Watt IHS dictates that the diffusion behavior of its component materials be known. This report describes the high temperature compatibility studies which were conducted on the component materials of the 60-Watt IHS.« less

Authors:
 [1];  [1]
  1. Mound Engineering & Analysis Group, Inc.
Publication Date:
Research Org.:
EG&G Mound Applied Technologies
Sponsoring Org.:
USDOE
OSTI Identifier:
1123675
DOE Contract Number:  
DE-AC04-88-DP43495
Resource Type:
Technical Report
Resource Relation:
Related Information: File Folder: Haupt H.8; STI input by OSTI for NE-75/SDPS
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPE AND RADIATION SOURCES; 36 MATERIALS SCIENCE; TUNGSTEN ALLOYS; HAFNIUM ALLOYS; RADIOISOTOPE HEAT SOURCES; CLADDING; IRIDIUM; MOLYBDENUM; WELDABILITY; TEMPERATURE RANGE 0400-1000 K; DATA; MECHANICAL PROPERTIES; COMPATIBILITY; NESDPS Office of Nuclear Energy Space and Defense Power Systems; tantalum alloy (T11); tungsten alloys; hafnium alloys; radioisotope heat sources; isotopic heat sources; cladding; iridium; molybdenum; oxidation resistance; weldability; high temperature; diffusivity; data; mechanical properties; compatibility

Citation Formats

Worley, C. M., and Merten, C. W. High Temperature Compatibility of 60-Watt IHS Materials. United States: N. p., 1995. Web. doi:10.2172/1123675.
Worley, C. M., & Merten, C. W. High Temperature Compatibility of 60-Watt IHS Materials. United States. doi:10.2172/1123675.
Worley, C. M., and Merten, C. W. Tue . "High Temperature Compatibility of 60-Watt IHS Materials". United States. doi:10.2172/1123675. https://www.osti.gov/servlets/purl/1123675.
@article{osti_1123675,
title = {High Temperature Compatibility of 60-Watt IHS Materials},
author = {Worley, C. M. and Merten, C. W.},
abstractNote = {The 60-Watt Isotopic Heat Source (IHS) utilizes a variety of materials which have been selected for their properties at elevated temperatures. These include iridium, molybdenum, and the T-111 alloy which consists of 90 wt% tantalum, 8 wt% tungsten, and 2 wt% hafnium. Properties of interest in radioisotopic heat source applications include high temperature strength, resistance to oxidation, weldability, and ability to act as a diffusion barrier. Iridium is utilized as a clad for fuel pellets because of its high temperature mechanical properties and good compatibility with carbon and plutonium oxide. Molybdenum retains good high temperature strength and has been used as a diffusion barrier in past applications. However, molybdenum also exhibits poor resistance to oxidation. Therefore, it is necessary to enclose molybdenum components so that they are not exposed to the atmosphere. T-111 exhibits moderate oxidation resistance, good high temperature mechanical properties, and good weldability. For these reasons, it is used as the outer containment boundary for the 60-Watt IHS. Because the temperature in GPHS fueled dads is on the order of 1000 degrees Celsius in the 60-W configuration, the potential for diffusion of dissimilar materials from one into another exists. Deleterious effects of diffusion can include degradation of mechanical strength through the formation of brittle intermetallics, degradation of mechanical properties through simple alloying, or formation of voids through the Kirkendall effect. Because of the possibility of these effects, design methodology calls for use of diffusion barriers between materials likely to exhibit interdiffusion at elevated temperatures. The necessity to assure the long term integrity of the 60-Watt IHS dictates that the diffusion behavior of its component materials be known. This report describes the high temperature compatibility studies which were conducted on the component materials of the 60-Watt IHS.},
doi = {10.2172/1123675},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {11}
}